Date: Fri, 28 Mar 2003 11:20:34 +1030 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: James Earl <mtntrip@telus.net>, Jaime <jaime@snowmoon.com>, James Earl <jdearl@telus.net> Cc: freebsd-questions@freebsd.org Subject: Re: Reverse DNS and single IP address space Message-ID: <20030328005034.GA72254@wantadilla.lemis.com> In-Reply-To: <20030327214336.GE645@comp4.ici.net> <20030327135506.A60255-100000@malkav.snowmoon.com> <20030327185204.GA645@comp4.ici.net> <20030327183154.GA622@comp4.ici.net> References: <20030327183154.GA622@comp4.ici.net> <20030327103827.A8705@mail.telestream.com> <20030327185204.GA645@comp4.ici.net> <20030327214336.GE645@comp4.ici.net> <20030327185204.GA645@comp4.ici.net> <20030327135506.A60255-100000@malkav.snowmoon.com> <20030327183154.GA622@comp4.ici.net> <20030327103827.A8705@mail.telestream.com> <20030327185204.GA645@comp4.ici.net> <20030327183154.GA622@comp4.ici.net>
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--azLHFNyN32YCQGCU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thursday, 27 March 2003 at 11:31:54 -0700, James Earl wrote: > I'm in the process of setting up primary and secondary name servers. > This is my first time setting up named so I'm kinda a newbie in this > area. > > My question is in regards to in-addr.arpa entries in named.conf and > zone files. In the FreeBSD Handbook and alot of other resources, I've > noticed how the ip address is reversed, with part of the address left > off. For example: > > zone "0.168.192.in-addr.arpa" { > type slave; > file "s/0.168.192.in-addr.arpa.bak"; > masters { > 192.168.1.1; > }; > }; This is a slave entry. It would be more interesting to see what the master config looks like. Anyway, this address is in an RFC 1918 non-routable address range. That means it's not unique, and it's completely meaningless on the global Internet. In fact, I have that address here :-) $ nslookup 192.168.0.1 Server: echunga.lemis.com Address: 192.109.197.82 Name: phantom.hidden.lemis.com Address: 192.168.0.1 > Now, what happens when I have only been allocated a single ip address > from my ISP (well, actually two, one for the primary/master and one for > the secondary/slave)? in-addr.arpa. addresses come in blocks of 256. You don't get the choice, your ISP has to provide reverse DNS. If he refuses, your only options are to find a new ISP or a /24 address range for which you can get reverse lookup. On Thursday, 27 March 2003 at 11:52:04 -0700, James Earl wrote: > On 2003.03.27 11:38 Victor Bondarenko wrote: >> On Thu, Mar 27, 2003 at 11:31:54AM -0700, James Earl wrote: >> [...] >>> Or, do I even need to worry about reverse DNS entries since my ISP >>> already has them setup? >> >> If your ISP has reverse DNS for your IP(s), there's really no point in >> you mapping them on your own. Your network might see whatever you've >> mapped, but the rest of the world will see what your ISP maps. > > I'm assuming if I can use nslookup [ip-address] to get my hostname, > that reverse DNS on the ISP is setup properly. Is this an okay > assumption? No. It depends on the name server you ask. If you have set up your name server as above, you'll get a response. Nobody else will, for the reasons mentioned above. On Thursday, 27 March 2003 at 13:55:37 -0500, Jaime wrote: >> I'm assuming if I can use nslookup [ip-address] to get my hostname, >> that reverse DNS on the ISP is setup properly. Is this an okay >> assumption? > > If you know enough about nslookup, then yes. I'd suggest "host > -v 1.2.3.4", though. Its a bit easier. :) Is that easier than "nslookup 1.2.3.4"? On Thursday, 27 March 2003 at 14:43:36 -0700, James Earl wrote: > Thanks for the help everyone! From your suggestions, it appears > reverse DNS is setup properly. Now if only my ISP could provide as > good of support, as all of you provided me! :) Unfortunately, most of it was wrong :-( Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply or reply to the original recipients. For more information, see http://www.lemis.com/questions.html See complete headers for address and phone numbers --azLHFNyN32YCQGCU Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE+g5xaIubykFB6QiMRAoNKAJ4mec2iCmznQqKriYPnzuyQxnvpQgCfdMlE TgaHukkJEanFH29Iuot8uUU= =iMgY -----END PGP SIGNATURE----- --azLHFNyN32YCQGCU--
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